#include <iostream>
#include <cstdio>
using namespace std;

int Max(int x, int y, int z)
{
	int m = x > y ? x : y;
	return m > z ? m : z;
}

int main()
{
	int a, b, c;
	cin >> a >> b >> c;
	double d = Max(a, b, c) * 1.0 / (Max(a + b, b, c) * Max(a, b, b + c));
	printf("%.3lf\n", d);
	
	return 0;
}
